FLT1 exhibited a causal relationship with obesity (OR: 0.939, 95% CI: 0.901–0.978, P = 0.002), GAP43 showed a causal relationship with obesity (OR: 0.897, 95% CI: 0.806–0.998, P = 0.046), and SLITRK1 was causally linked to obesity (OR: 0.855, 95% CI: 0.736–0.994, P = 0.041). The gene discussed is GAP43; the disease is obesity due to melanocortin 4 receptor deficiency.